Electric and electronic components such as a board (a substrate) on which various LSI chips such as a CPU and so forth are loaded, storage devices such as a hard disk drive (HDD), a solid-state drive (SSD) and so forth, a power source device, input/output devices and so forth are loaded on an electronic apparatus such as, for example, a computer system and so forth, and housed in a chassis of the electronic apparatus and the respective electric and electronic components generate heat with operations thereof. A fixed temperature range is defined in a specification for these electric and electronic components in order to ensure favorable operations thereof. Accordingly, the electronic apparatus is equipped with a cooling fan which discharges heat generated in the chassis to the outside of the chassis in order to maintain the temperature in the chassis within the fixed temperature range.
When the cooling fan operates, an operation sound is generated. A user may hear this operation sound as noise. Therefore, a technique of reducing the operation sound of the cooling fan while maintaining sufficient cooling capacity of the cooling fan is proposed. For example, in Japanese Patent Application Laid-Open No. 2007-122276, there is disclosed a technique of making it possible to reduce an unpleasant feeling of the user caused by the operation sound of the cooling fan and to suppress unnecessary power consumption by stopping rotation of the cooling fan in a case where it is decided that a falling speed of the temperature in a computer chassis remains constant in a predetermined set temperature range.